The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC manufacturing are needed.
For example, in semiconductor technologies, a plurality of photomasks (masks) are formed with predesigned IC patterns. The plurality of masks are used during lithography processes to transfer predesigned IC patterns into a plurality of exposure fields on a semiconductor wafer.
During the photolithography illumination process, the IC pattern on the photomask should be free of any foreign particles and debris. To prevent such debris from collecting on the photomask during transportation and storage, pellicles are often secured to the photomask to protect the IC pattern. A pellicle typically includes a thin film stretched across a frame that is secured to the mask by an adhesive or other semi-permanent or permanent fastener. The frame holds the film a distance above the mask pattern such that particles deposited on the film will be out of focus during illumination of the mask. In some instances, when a pellicle is mounted to a photomask, the force of pellicle frame induces distortion in the photomask. Such distortion may negatively influence the IC pattern transferred to a semiconductor wafer.
Thus, although existing approaches and structures utilized to mount a pellicle on a photomask have been satisfactory for their intended purposes, they have not been entirely satisfactory in all respects.